This invention relates to fuel injection pumps for internal combustion engines, and more particularly to an in-line type fuel injection pump which facilitates machining of its pump housing.
An in-line type fuel injection pump in general for use with a Diesel engine has a plurality of pump assemblies formed essentially of plungers and plunger barrels corresponding in number to the cylinders of the engine and arranged in a line. Each of the pump assemblies is accommodated in a pump accommodating space formed in the pump housing and has a fuel chamber formed in the pump accommodating space and supplied with fuel from a fuel tank, via a fuel intake connector mounted on the pump housing and connected to the fuel tank. Conventional measures for guiding fuel from the fuel intake connector to the fuel chamber of each of the pump assemblies include a method of boring the fuel chamber to a large interior diameter so that the fuel chambers of adjacent pump assemblies are in communication with each other, at least one of which is in communication with the fuel intake connector, a method of forming communication holes in the pump housing, each communicating the fuel chamber of its corresponding pump assembly with the fuel intake connector, and a method of forming a lateral side hole in the pump housing, which opens in the fuel chamber of each pump assembly, so as to communicate the fuel chambers with each other by the side hole, at least one of the fuel chambers being in communication with the fuel intake connector.
However, any of the above conventional measures requires complicate machining, especially boring, of the pump housing, and the more the number of the pump assemblies of the pump, the more difficult such machining becomes. This results in low productivity and accordingly a high manufacturing cost of the pump, as well as in difficulties in designing the pump compact in size.